The Washington Redskins concluded their three-day rookie minicamp today, and Coach Mike Shanahan came away from it with a sense of encouragement from what he saw in rookie defensive backs David Amerson, Phillip Thomas and Bacarri Rambo.

The size, athleticism and instincts that made all three attractive to the Redskins were evident on the field today – the only practice session open to the media.

“It was real impressive to see our draft choices and see their size and speed and their quickness, the things we were hoping for,” Shanahan said. “Their ball skills were very evident out there the last few days. It was a good practice.”

Amerson, whom Shanahan has said the team will groom to play on the outside, worked almost exclusively at right cornerback. There were a couple times where he lined up on the left side, but Amerson said over the last three days (five practice sessions), right corner is where he has spent the bulk of his time.

Amerson showed good speed and used his long arms to create some problems for the receivers he went against. He showed some physicality at the line when playing press coverage.

Amerson played in a rather different system at N.C. State, so he spent the weekend familiarizing himself with Washington’s scheme. He said he’s excited about the playmaking opportunities that playing in the Redskins’ system will afford him.

“I think the defense is very corner-friendly,” Amerson said. “At N.C. State, our corners were often out on an island. But here, you’ve got a lot of help over the top so you can be aggressive when it comes to jumping routes and things like that, and that’s how I love to play.”

Thomas and Rambo shared the field with Thomas lining up predominantly at strong safety and Rambo at free safety. There were times when the offensive formation and motions required Rambo to play up in the box while Thomas dropped back and played deep. Other times, they both played deep.

They certainly passed the eyeball test. Both boast good size, move with fluidity and good anticipation while backpedaling and changing directions, and then fly to the ball. They made decisions quickly and played fast.

Thomas recorded an interception over the middle of the field, and he also forced a fumble when in coverage of wide receiver Skye Dawson, who made a catch as he ran a slant. Thomas swatted and knocked the ball out of Dawson’s grasp, and scooped up the loose ball.

Rambo also had an interception downfield as he went up in traffic and wrestled a Ryan Radcliff pass away from wide receiver Jason Thompson.

At one point, Rambo backpedaled at the snap of the ball and then changed directions and closed in on wideout Antavian Edison, who made a catch on a short route. Rambo pulled up just as he got to the receiver because these are non-contact drills.

“Oh!” Raheem Morris shouted as Rambo flew to the ball. “Good night!”

Rambo would’ve laid Edison out had he not held up.

“It’s kind of better than I thought it was going to go,” Rambo said. “Came out here and just learned what to do. Kind of carried over from what we did at Georgia. Coach Kirk Olivadotti, who’s a linebacker’s coach there, used to be here, so I had a year to learn things from him and they carried over, and I’m just taking advantage of everything and learning the scheme. Learning the scheme, learning technique and coverage, and it was all natural after that.”

For Thomas, the concepts that Washington’s defense runs were all familiar. At Fresno State, the Bulldogs ran virtually the same system. So the only thing that was foreign for Thompson was the terminology. But he understood his role well.

“I felt comfortable playing wherever they play me: strong, free, wherever,” the fourth-round pick said. “We repped it a little bit this week and I got comfortable as the week went along.”

Asked what ranks at the top of his to-do list as he works to ready himself for his first NFL season, Thomas said: “Technique. Technique and everything. Everybody’s a lot faster and a lot better at this level and you have to have great technique to keep up with these dudes who are running 4.2 and 4.3’s and technique is what’s going to help you make up for speed.”

As Matt Bowen explained in a post that ran Friday, the safety position is highly demanding, especially for rookies. But Shanahan said that both Rambo and Thomas have shown great learning ability and work ethic as they dig into the playbook.

“Well, when we drafted them – we have different tests that they take that tell us what type of mental quickness they have and what type of dedication, commitment – those types of things that are very important to us,” Shanahan said. “Those two guys – one had a 10, one had a nine out of a 10-point [scale], so that’s as good as you see and that’s what you’re hoping for.”

Some other observations from rookie minicamp:

Tight end Jordan Reed – the player Washington selected in the round prior to Thomas – did not partake in the minicamp practices because he still is healing from an injury to his left knee/quad. He suffered it in the final game of his college career, but says he is close to being fully healed.

Running back Chris Thompson also watched as well, healing from surgery to repair a torn ACL. Shanahan said that he remains on target to be a full participant by the start of training camp.

Outside linebacker Brandon Jenkins, who missed nearly all of his final season at Florida State with a foot injury, has fully healed and was on the field in unlimited capacity.

Alfred Morris’s little brother, Shawn Morris, was a minicamp tryout participant. A Division III all-American from Birmingham Southern, Shawn Morris also is a running back. He said being Alfred Morris’s brother no doubt put him on the Redskins’ radar, but said Alfred didn’t pull any strings to get him a tryout. The Redskins called Shawn’s agent the night after the draft to extend an invitation. Shawn Morris is 5-foot-7, 196 pounds, and looks more the part of a faster third-down back than the punishing runner that Alfred is.

Dawson made a couple nice catches and showed off impressive speed as well as leaping ability.

It was hard to get a good read on who was exceptional, besides Amerson, Thomas and Rambo, as many of the players still were very much in a learning process.

The oddest element of the minicamp was the absence of special teams coach Danny Smith, whose distinct voice and high energy level used to be a staple at Redskins practices. He, of course, is now in Pittsburgh.

The Redskins didn’t work on full-team special teams work at the rookie minicamp. New special teams coach Keith Burns did, however, spend time working with a pair of punters, Jackson Rice and Dylan Breeding, and long-snapper Jordan Cowart, during practice.

The rookies all left Redskins Park on Sunday afternoon, and the draft picks and signed undrafted free agents will return for the start of OTAs on May 20. Shanahan said he told the 48 tryout players to keep working out, stay in shape and keep chasing their dreams because you never know when your next opportunity will present itself.

Have a Redskins question? E-mail Mike Jones at mike.jones@washpost.com with the subject line “Mailbag question” for him to answer it in the Monday Mailbag.